Hyperspectral imaging method and device based on diffractive lens and electronic equipment

Abstract

The invention relates to a hyperspectral imaging method and device based on a diffraction lens and electronic equipment. The method comprises the following steps: determining a target focusing distance of target light with a target wavelength after passing through a target diffraction lens; determining a target blurring kernel corresponding to the target light at the target focusing distance; determining a coded image of the target light at the target focusing distance; and determining a single spectrum channel image corresponding to the target wavelength according to the target blurring kernel and the coded image. According to the embodiment of the invention, the target focusing distance corresponding to the target wavelength can be determined to reconstruct the specified spectral channel, and other spectral channels except the spectral channel corresponding to the target wavelength do not need to be reconstructed, so that the efficiency and flexibility of spectral imaging are improved; and the spectral resolution can be converted into the resolution of the target focusing distance, so that a plurality of continuous spectral channel images with higher resolution can be quickly obtained by reconstructing the coded images at the target focusing distances with different values.

Description

Technical Field

[0001] The present disclosure relates to the technical field of spectral imaging and image processing, and in particular to a hyperspectral imaging method, device and electronic equipment based on a diffraction lens. Background Art

[0002] Spectral imaging technology can simultaneously obtain the two-dimensional spatial information of the observed target and the spectral information at each spatial position, forming a three-dimensional spectral cube data. The commonly used spectral imaging technologies in the prior art include scanning spectral imaging and snapshot spectral imaging. The raw data collected by these imaging methods usually destroy the structure of the image space domain, resulting in the inability to image the specified spectral channel during the observation process, lacking mobility and flexibility. Summary of the invention

[0003] In view of this, the present disclosure proposes a technical solution of a hyperspectral imaging method, device and electronic equipment based on a diffraction lens.

[0004] According to one aspect of the present disclosure, a hyperspectral imaging method based on a diffractive lens is provided, including: determining a target focusing distance of a target light having a target wavelength after passing through a target diffractive lens; determining a target blur kernel corresponding to the target light at the target focusing distance; determining an encoded image of the target light at the target focusing distance; and determining a single spectral channel image corresponding to the target wavelength based on the target blur kernel and the encoded image.

[0005] In one possible implementation, determining the target focusing distance of a target light ray having a target wavelength after passing through a target diffraction lens includes: determining, based on the target wavelength, a phase difference generated after the target light ray passes through the target diffraction lens; and determining the target focusing distance based on the phase difference generated after the target light ray passes through the target diffraction lens.

[0006] In a possible implementation, the phase difference generated after the target light passes through the target diffraction lens includes: a first phase difference when the target light passes through any point other than the center point of the target diffraction lens relative to the target light passing through the center point of the target diffraction lens, and a second phase difference caused by the optical path difference when the target light passes through any point other than the center point of the target diffraction lens to propagate to the focus relative to the target light passing through the center point of the target diffraction lens to the focus; determining the phase difference generated after the target light passes through the target diffraction lens according to the target wavelength includes: for any point on the target diffraction lens, determining the first phase difference corresponding to the target light passing through the point according to the target wavelength and the lens surface parameters corresponding to the target diffraction lens; for any point on the target diffraction lens, determining the second phase difference corresponding to the target light passing through the point according to the target wavelength.

[0007] In one possible implementation, the target blur kernel includes a three-dimensional spectral point spread function; determining the target blur kernel corresponding to the target light at the target focusing distance includes: determining a transmittance function corresponding to the target diffraction lens; and determining the three-dimensional spectral point spread function based on the target focusing distance and the transmittance function.

[0008] In one possible implementation, the target blur kernel includes a three-dimensional spectral point spread function; determining the single spectral channel image corresponding to the target wavelength based on the target blur kernel and the encoded image includes: using a digital confocal algorithm to reconstruct the encoded image based on the three-dimensional spectral point spread function to determine the single spectral channel image corresponding to the target wavelength.

[0009] In one possible implementation, determining the single spectral channel image corresponding to the target wavelength based on the target blur kernel and the encoded image includes: utilizing a deep learning algorithm to reconstruct the encoded image based on the target blur kernel to determine the single spectral channel image corresponding to the target wavelength.

[0010] In a possible implementation, the target diffractive lens is processed according to target lens surface parameters, wherein the target lens surface parameters are determined according to the center wavelength, the center focal length and the material refractive index corresponding to the target material, and the target material represents the material used to process the target diffractive lens.

[0011] According to another aspect of the present disclosure, a hyperspectral imaging device based on a diffraction lens is provided, including: a focusing distance determination module, used to determine a target focusing distance of a target light with a target wavelength after passing through a target diffraction lens; a blur kernel determination module, used to determine a target blur kernel corresponding to the target light at the target focusing distance; an image acquisition module, used to determine an encoded image of the target light at the target focusing distance; and an image reconstruction module, used to determine a single spectral channel image corresponding to the target wavelength based on the target blur kernel and the encoded image.

[0012] According to another aspect of the present disclosure, an electronic device is provided, comprising: a processor; and a memory for storing processor-executable instructions; wherein the processor is configured to implement the above method when executing the instructions stored in the memory.

[0013] According to another aspect of the present disclosure, a non-volatile computer-readable storage medium is provided, on which computer program instructions are stored, wherein the computer program instructions implement the above method when executed by a processor.

[0014] In the disclosed embodiment, by determining the target focusing distance after the target light having the target wavelength passes through the target diffraction lens, the target blur kernel corresponding to the target light at the target focusing distance can be determined, as well as the encoded image of the target light at the target focusing distance; based on the target blur kernel and the encoded image, the single spectral channel image corresponding to the target wavelength can be determined, so that the designated spectral channel can be reconstructed separately without the need to reconstruct other spectral channels other than the spectral channel corresponding to the target wavelength, thereby improving the efficiency and flexibility of spectral imaging. On this basis, by flexibly setting the value of the target wavelength, the spectral resolution can be converted into the resolution of the target focusing distance, so that based on the change of the target focusing distance with the value of the target wavelength, by reconstructing the encoded images at the target focusing distances with different values, multiple continuous spectral channel images with higher resolution can be quickly and conveniently obtained.

[0015] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0017] Figure 1 A flow chart showing a hyperspectral imaging method based on a diffraction lens according to an embodiment of the present disclosure is shown;

[0018] Figure 2A schematic diagram showing a Fresnel diffraction lens according to an embodiment of the present disclosure is shown;

[0019] Figure 3 A schematic diagram showing the diffraction and propagation of a light ray through a diffraction lens according to an embodiment of the present disclosure;

[0020] Figure 4 A schematic diagram showing a coded image of a target wavelength with different values ​​and a corresponding blur kernel according to an embodiment of the present disclosure;

[0021] Figure 5 A schematic diagram showing a comparison between a coded image and a single spectral channel image according to an embodiment of the present disclosure is shown;

[0022] Figure 6 A block diagram of a hyperspectral imaging device based on a diffraction lens according to an embodiment of the present disclosure is shown;

[0023] Figure 7 A block diagram of an electronic device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0024] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0025] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0026] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0027] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present disclosure.

[0028] Through spectral imaging technology, the two-dimensional spatial information of the observed target object and the spectral information at each spatial position can be obtained simultaneously, thereby forming a three-dimensional spectral cube data, namely a hyperspectral image. According to any pixel on the hyperspectral image, the complete spectral curve corresponding to the pixel can be obtained to reflect the chemical composition, physical state, and other properties related to the spectral response of the substance corresponding to the pixel. Therefore, spectral imaging technology is widely used in earth observation, mineral resource exploration, environmental pollution monitoring, crop pest and disease monitoring and other fields.

[0029] Since a single acquisition of an image sensor can only obtain two-dimensional spatial data corresponding to the target object, it is necessary to obtain three-dimensional spectral data through scanning or post-processing algorithms to achieve spectral imaging. Spectral imaging technologies commonly used in the prior art include scanning spectral imaging and snapshot spectral imaging. Specifically, a hyperspectral camera using scanning spectral imaging can use prisms and gratings to achieve spectral separation, and use a scanning structure to perform spatial scanning of the scene, obtain the reflected light or transmitted light of the object point by point or line by line, and thus obtain three-dimensional spectral data. The snapshot spectral imaging method can be based on a coding device to collect a single two-dimensional coded image with overlapping spatial information and spectral information, and then use the principle of compressed sensing to reconstruct the two-dimensional coded image to obtain a hyperspectral image.

[0030] However, the raw image data obtained by scanning spectral imaging or snapshot spectral imaging destroys the structure of the image space domain and cannot image the specified spectral channel during the observation process. These imaging methods lack mobility and flexibility. On the other hand, the amount of raw image data collected by snapshot spectral imaging is small, resulting in low spectral resolution of the reconstructed hyperspectral image.

[0031] In view of this, the present disclosure provides a hyperspectral imaging method based on a diffractive lens, which can achieve reconstruction of the spectral channel corresponding to the target wavelength by determining the target focusing distance corresponding to the target wavelength, without the need to reconstruct other spectral channels other than the spectral channel corresponding to the target wavelength, thereby improving the efficiency and flexibility of spectral imaging. The hyperspectral imaging method based on a diffractive lens provided by the present disclosure is described in detail below.

[0032] Figure 1A flow chart of a hyperspectral imaging method based on a diffractive lens according to an embodiment of the present disclosure is shown. The hyperspectral imaging method based on a diffractive lens can be executed by an electronic device such as a terminal device or a server. The terminal device can be a user equipment (UE), a mobile device, a user terminal, a terminal, a cellular phone, a cordless phone, a personal digital assistant (PDA), a handheld device, a computing device, a vehicle-mounted device, a wearable device, etc. The hyperspectral imaging method based on a diffractive lens can be implemented by a processor calling computer-readable instructions stored in a memory. Alternatively, the hyperspectral imaging method based on a diffractive lens can be executed by a server. Figure 1 As shown, the hyperspectral imaging method based on the diffraction lens includes:

[0033] In step S11, a target focusing distance of a target light beam having a target wavelength after passing through a target diffractive lens is determined.

[0034] The target wavelength here may represent the wavelength corresponding to the specified spectral channel, and its specific number and specific value may be flexibly set according to actual use requirements, and the present disclosure does not specifically limit this. The target diffraction lens may represent an optical element that works based on the diffraction principle, and may be used to realize the reconstruction of single spectral channel images corresponding to multiple different wavelengths. Its specific form may refer to the implementation methods in the related art, for example, the target diffraction lens may be a Fresnel diffraction lens, etc., and the present disclosure does not specifically limit this.

[0035] Figure 2 FIG. 1 is a schematic diagram of a Fresnel diffraction lens according to an embodiment of the present disclosure. Figure 2 As shown, the Fresnel diffraction lens includes a plurality of ring structures with different etching depths, wherein the dark ring corresponds to a lower etching depth, and the light ring corresponds to a higher etching depth.

[0036] In a possible implementation, the target diffractive lens is processed according to the target lens surface parameters, wherein the target lens surface parameters are determined according to the center wavelength, the center focal length and the material refractive index corresponding to the target material, and the target material represents the material used to process the target diffractive lens.

[0037] The target lens surface parameters can reflect the shape characteristics and size characteristics of the target diffractive lens. The specific content can be flexibly set according to actual usage requirements. For example, it can include the diameter corresponding to the target diffractive lens, the center point thickness, the etching depth corresponding to each position on the target diffractive lens, the radius of the clear aperture of the target diffractive lens, etc. The present disclosure does not make specific limitations on this.

[0038] The target lens surface parameters can be determined according to the central wavelength, central focal length and the material refractive index corresponding to the target material. Among them, the central wavelength and the central focal length can be flexibly set according to the actual use requirements. For example, the central wavelength can be determined according to the wavelength range of the light to be observed, and the central focal length corresponding to the central wavelength can be determined to meet the requirements of reconstructing a single-channel spectral image corresponding to any wavelength in the wavelength range, etc. The present disclosure does not make specific restrictions on this; the specific form of the target material can be flexibly set according to the actual use requirements, for example, a transparent glass substrate, etc. The present disclosure does not make specific restrictions on this; the material refractive index corresponding to the target material can include the refractive index of the target material for the target light, and its specific value can refer to the implementation method in the relevant technology, and the present disclosure does not make specific restrictions on this.

[0039] The specific method of determining the target lens surface parameters according to the central wavelength, central focal length and the material refractive index corresponding to the target material can be referred to the implementation methods in the relevant technology, and the present disclosure does not make specific limitations on this.

[0040] In one example, the target lens surface parameters include the etching depth corresponding to each position on the target diffractive lens; determining the target lens surface parameters according to the center wavelength, the center focal length and the material refractive index corresponding to the target material may include: determining, according to the center wavelength, the center focal length and the material refractive index corresponding to the target material, a first phase difference of a light ray with the center wavelength passing through any point other than the center point of the target diffractive lens relative to a light ray with the center wavelength passing through the center point of the target diffractive lens, and a second phase difference caused by an optical path difference when a light ray with the center wavelength passes through any point other than the center point of the target diffractive lens to propagate to the center focal length relative to a light ray with the center wavelength passing through the center point of the target diffractive lens to propagate to the center focal length; based on the first phase difference and the second phase difference, the etching depth corresponding to each position on the target diffractive lens may be determined.

[0041] Figure 3 FIG. 1 is a schematic diagram showing a light beam diffracted and propagated through a diffractive lens according to an embodiment of the present disclosure. Figure 3 As shown, for a light with a central wavelength, when the light passes through any point other than the center point of the target diffractive lens, due to the different propagation speeds of the light in the air and the target material corresponding to the target diffractive lens, the thickness difference between the point and the center point corresponding to the target diffractive lens will cause the propagation light field of the light to change in phase, thereby generating a corresponding first phase difference. Specifically, the first phase difference can be expressed as formula (1):

[0042]

[0043] Among them, Δφ h (r,λ c) represents the first phase difference; r represents the radial coordinate of the target diffraction lens; λ c represents the central wavelength; Indicates that the target material has a central wavelength λ c The material refractive index of the light with the central wavelength λ c The refractive index of the light; Δh(r) represents the etching depth corresponding to the radial coordinate r of the target diffractive lens.

[0044] With the above Figure 3 For example, Figure 3 As shown, for a light ray with a central wavelength, after the light ray passes through the target diffraction lens, the optical path from different positions on the target diffraction lens to the focus is different.

[0045] Therefore, when the light passes through any point other than the center point of the target diffractive lens to the center focal length, a second phase difference will be generated due to the optical path difference relative to when the light passes through the center point of the target diffractive lens to the center focal length. The second phase difference can be expressed as formula (2):

[0046]

[0047] Among them, Δφ g (r,λ c ) represents the second phase difference; f represents the central focal length.

[0048] Therefore, the phase difference Δφ generated by the light with the central wavelength after passing through the target diffraction lens can be expressed as formula (3):

[0049] Δφ=Δφ g (r,λ c )+Δφ h (r,λ c ) (3)

[0050] In order to achieve the effect of interference enhancement, for a light ray with a central wavelength, the phase difference Δφ generated after the light ray passes through any point on the target diffraction lens needs to be equal to an integer multiple of 2π. This quantitative condition can be expressed as formula (4):

[0051] Δφ=Δφ g (r,λ c )+Δφ h (r,λ c )=2mπ (4)

[0052] Here, m is an integer, and its specific value can be flexibly set according to actual usage requirements, and the present disclosure does not make any specific limitation on this.

[0053] According to formula (1) to formula (4), the etching depth corresponding to the radial coordinate r of the target diffractive lens can be solved. The etching depth corresponding to the radial coordinate r of the target diffractive lens can be expressed as formula (5):

[0054]

[0055] Furthermore, in order to facilitate the processing of the target diffractive lens, the etching depth needs to be limited to On this basis, the etching depth corresponding to the radial coordinate r of the target diffractive lens can be expressed as formula (6):

[0056]

[0057] Among them, rem represents the remainder operation.

[0058] In the prior art, a diffractive lens is usually processed by multiple overlays. Therefore, the etching depth corresponding to the radial coordinate r of the target diffractive lens can be quantified into a preset number of steps to obtain a quantized etching depth. The preset number satisfies an integer power of 2, and its specific value can be flexibly set according to actual usage requirements, and the present disclosure does not make specific limitations on this.

[0059] Taking the etching depth corresponding to the radial coordinate r of the target diffractive lens as quantized into 8 steps as an example, the quantized etching depth can be expressed as formula (7):

[0060]

[0061] in, Indicates the quantized etching depth; round indicates rounding operation; Δh max Indicates the maximum etching depth.

[0062] According to the quantitative etching depth, the target material can be overlaid for multiple times to obtain the target diffractive lens.

[0063] Based on the target diffractive lens, the target focusing distance of the target light with the target wavelength after passing through the target diffractive lens can be determined. The specific method of determining the target focusing distance can refer to the implementation in the relevant technology, and this disclosure does not make specific limitations on this.

[0064] The specific process of determining the target focusing distance of the target light with the target wavelength after passing through the target diffraction lens will be described in detail later in combination with possible implementation methods of the present disclosure, and will not be elaborated here.

[0065] In step S12, a target blur kernel corresponding to the target light at the target focusing distance is determined.

[0066] According to the target focusing distance, the target blur kernel of the target light with the target wavelength propagating through the target diffraction lens to the target focusing distance can be determined based on the diffraction propagation algorithm, so as to be used for the subsequent reconstruction of the hyperspectral image of the specified spectral channel. Among them, the specific form of the target blur kernel can be flexibly set according to the actual use requirements. For example, the target blur kernel can include a three-dimensional spectral point spread function, etc., which is not specifically limited in this disclosure; the specific method of determining the target blur kernel can refer to the implementation method in the relevant technology, which depends on the form of the target blur kernel, which is not specifically limited in this disclosure.

[0067] The specific process of determining the target blur kernel corresponding to the target light at the target focusing distance will be described in detail later in conjunction with possible implementation methods of the present disclosure, and will not be elaborated here.

[0068] In step S13, a coded image of the target light at the target focusing distance is determined.

[0069] The image acquisition device can be used to determine the coded image of the target light at the target focusing distance. The specific form of the image acquisition device here can be flexibly set according to actual use requirements, such as a monochrome image sensor, etc., and this disclosure does not make specific limitations on this.

[0070] Through the above process, the dispersion form of the target diffraction lens can be used to map the spectral channel image of the target wavelength to the focal plane at the target focusing distance along the optical axis. By flexibly setting the value of the target wavelength, the spectral resolution can be converted into the resolution of the target focusing distance, so that a continuous encoded image can be obtained based on the change of the target focusing distance with the value of the target wavelength, and then a continuous spectral channel image can be subsequently reconstructed, and the spectral resolution of the spectral channel image can be improved.

[0071] In step S14, a single spectral channel image corresponding to the target wavelength is determined according to the target blur kernel and the encoded image.

[0072] According to the target blur kernel, the encoded image of the target light with the target wavelength at the target focusing distance can be directly reconstructed to obtain a single spectral channel image corresponding to the target wavelength, so as to achieve reconstruction of the specified spectral channel alone without the need to reconstruct other spectral channels other than the spectral channel corresponding to the target wavelength, thereby improving the efficiency and flexibility of spectral imaging. By adjusting the value of the target wavelength and performing spectral imaging using the above process, multiple discrete single spectral channel images can be obtained.

[0073] Furthermore, based on the hyperspectral imaging method based on the diffraction lens provided by the embodiment of the present disclosure, it is also possible to simplify the structure and volume of the hyperspectral imaging system, without the need for an additional scanning device or encoding device, so that the hyperspectral imaging system only needs a target diffraction lens and a monochrome image sensor to achieve high-resolution hyperspectral imaging, which can be applied to low-load application scenarios such as light aircraft, drones, and satellites. In addition, by flexibly setting the value of the target wavelength, the spectral resolution can be converted into the axial displacement resolution of the monochrome image sensor, and by adjusting the axial distance between the monochrome image sensor and the target diffraction lens, the encoded images at the target focusing distances of different values ​​are collected, and the spectral data is reconstructed to obtain a continuous spectral channel image.

[0074] In the disclosed embodiment, by determining the target focusing distance after the target light having the target wavelength passes through the target diffraction lens, the target blur kernel corresponding to the target light at the target focusing distance can be determined, as well as the encoded image of the target light at the target focusing distance; based on the target blur kernel and the encoded image, the single spectral channel image corresponding to the target wavelength can be determined, so that the designated spectral channel can be reconstructed separately without the need to reconstruct other spectral channels other than the spectral channel corresponding to the target wavelength, thereby improving the efficiency and flexibility of spectral imaging. On this basis, by flexibly setting the value of the target wavelength, the spectral resolution can be converted into the resolution of the target focusing distance, so that based on the change of the target focusing distance with the value of the target wavelength, by reconstructing the encoded images at the target focusing distances with different values, multiple continuous spectral channel images with higher resolution can be quickly and conveniently obtained.

[0075] In one possible implementation, determining a target focusing distance of a target light ray having a target wavelength after passing through a target diffraction lens includes: determining a phase difference generated after the target light ray passes through the target diffraction lens based on the target wavelength; and determining the target focusing distance based on the phase difference generated after the target light ray passes through the target diffraction lens.

[0076] According to the target wavelength, the phase difference generated by the target light having the target wavelength after passing through the target diffractive lens can be determined. The specific method of determining the phase difference generated by the target light after passing through the target diffractive lens can refer to the implementation in the relevant technology, and the present disclosure does not make specific limitations on this.

[0077] In a possible implementation, the phase difference generated after the target light passes through the target diffraction lens includes: a first phase difference when the target light passes through any point other than the center point of the target diffraction lens relative to the target light passing through the center point of the target diffraction lens, and a second phase difference caused by the optical path difference when the target light passes through any point other than the center point of the target diffraction lens to propagate to the focus relative to the target light passing through the center point of the target diffraction lens to propagate to the focus; determining the phase difference generated after the target light passes through the target diffraction lens according to the target wavelength, including: for any point on the target diffraction lens, determining the first phase difference corresponding to the target light passing through the point according to the target wavelength and the lens surface parameters corresponding to the target diffraction lens; for any point on the target diffraction lens, determining the second phase difference corresponding to the target light passing through the point according to the target wavelength.

[0078] For a target light with a target wavelength, when the target light passes through any point other than the center point of the target diffractive lens, due to the different propagation speeds of the light in the air and the target material corresponding to the target diffractive lens, the thickness difference between the point and the center point corresponding to the target diffractive lens will cause the propagation light field of the light to change in phase, thereby generating a corresponding first phase difference. Therefore, for any point on the target diffractive lens, according to the target wavelength and the lens surface parameters corresponding to the target diffractive lens, the first phase difference corresponding to the target light passing through the point can be determined.

[0079] In one example, the lens surface parameters corresponding to the target diffractive lens include: the quantized etching depth corresponding to the radial coordinate r of the target diffractive lens, and the first phase difference can be expressed by formula (8):

[0080]

[0081] Among them, Δφ h (r, λ) represents the first phase difference corresponding to any point on the target diffraction lens when the target light passes through it; λ represents the target wavelength; n λ Indicates the material refractive index of the target material for the target light with the target wavelength λ.

[0082] For the target light with the target wavelength, after the target light passes through the target diffractive lens, the optical path from different positions on the target diffractive lens to the focus is different. Therefore, when the target light passes through any point other than the center point of the target diffractive lens to the focus, a second phase difference will be generated due to the optical path difference relative to when the target light passes through the center point of the target diffractive lens to the focus. For any point on the target diffractive lens, the second phase difference corresponding to the target light passing through the point can be determined according to the target wavelength.

[0083] In one example, the second phase difference can be expressed as formula (9):

[0084]

[0085] Among them, Δφ g (r, λ) represents the second phase difference corresponding to the target light passing through any point on the target diffraction lens; z represents the target focusing distance, which is an unknown quantity.

[0086] It can be seen from the above formula (9) that the specific value of the second phase difference generated after the target light passes through the target diffraction lens is affected by the target focusing distance. Therefore, by analyzing the first phase difference and the second phase difference generated after the target light passes through the target diffraction lens, the target focusing distance can be solved.

[0087] Specifically, in order to achieve the effect of interference enhancement, the phase difference generated by the target light after passing through the target diffraction lens needs to be equal to an integer multiple of 2π. This quantitative condition can be expressed as formula (10):

[0088]

[0089] Generally, the refractive index of the target material changes little to light with different wavelengths, and the error range of the quantitative etching depth corresponding to the target diffractive lens is controllable. Therefore, the target diffractive lens can be used to quantize the etching depth with a central wavelength λ c The material refractive index of the light The material refractive index n of the target light having the target wavelength λ of the alternative target diffractive lens λ ; Use the etching depth Δh(r) corresponding to the radial coordinate r of the target diffractive lens to replace the quantitative etching depth corresponding to the radial coordinate r of the target diffractive lens To simplify formula (10).

[0090] Furthermore, based on the above Figure 3 For example, Figure 3 As shown in the figure, the etching depth Δh(r) corresponding to the radial coordinate r of the target diffractive lens forms a sawtooth distribution after the remainder operation. The corresponding phase distribution when the target light passes through the target diffractive lens is similar to that with the central wavelength λ c The phase distribution of the light passing through the target diffraction lens is similar. Therefore, formula (4) and formula (10) can be simplified together to obtain formula (11):

[0091]

[0092] Usually, the central focal length corresponding to the target diffractive lens is much larger than the radial coordinate r of the target diffractive lens. Therefore, formula (11) can be simplified to formula (12):

[0093]

[0094] The target focusing distance can be determined according to formula (12). Specifically, the target focusing distance can be expressed as formula (13):

[0095]

[0096] According to formula (13), the focusing distance of the light with the target wavelength passing through the target diffractive lens can be quickly determined. On this basis, by flexibly setting the value of the target wavelength, the spectral resolution can be converted into the resolution of the target focusing distance.

[0097] In one possible implementation, the target blur kernel includes a three-dimensional spectral point spread function; determining the target blur kernel corresponding to the target light at the target focusing distance includes: determining the transmittance function corresponding to the target diffraction lens; and determining the three-dimensional spectral point spread function based on the target focusing distance and the transmittance function.

[0098] For the target light with the target wavelength, the transmittance function of the target diffractive lens for the target light with the target wavelength can be determined in combination with the lens surface parameters of the target diffractive lens. Specifically, the transmittance function can be expressed as formula (14):

[0099]

[0100] Wherein, t(x, y, λ) represents the transmittance function of the target diffractive lens for the target light with the target wavelength; cric(·) represents the circular domain function; R represents the radius of the clear aperture corresponding to the target diffractive lens; Represents the quantized etching depth of the point with coordinates (x, y) on the target diffractive lens.

[0101] The target light is modulated by the target diffraction lens and propagates to the focal plane at the target focusing distance. The intensity distribution generated by different wavelengths at the focal plane can be represented by the three-dimensional spectral point spread function. Specifically, based on the diffraction integral formula, the three-dimensional spectral point spread function can be expressed as formula (15):

[0102]

[0103] Wherein, p(x, y, λ) represents the three-dimensional spectral point spread function; i represents the imaginary unit; x0 and y0 represent the abscissa and ordinate of the plane corresponding to the target diffractive lens, respectively.

[0104] Figure 4 A schematic diagram showing a coded image of a target wavelength with different values ​​and a corresponding blur kernel according to an embodiment of the present disclosure is shown. Figure 4 As shown in (a) in FIG. 1 , the image represents the coded image corresponding to the light with a wavelength of 540 nm; Figure 4 As shown in (b) in FIG. 1 , the image represents the coded image corresponding to the light with a wavelength of 550 nm; Figure 4 As shown in (c) in FIG. 1 , the image represents the coded image corresponding to the light with a wavelength of 560 nm; Figure 4 As shown in (d) in FIG. 1 , the image represents the spectral point spread function corresponding to light with a wavelength of 540 nm; Figure 4 As shown in (e) in FIG. 1 , the image represents the spectral point spread function corresponding to light with a wavelength of 550 nm; Figure 4 As shown in (f), the image represents the spectral point spread function corresponding to light with a wavelength of 560nm.

[0105] In one possible implementation, the target blur kernel includes a three-dimensional spectral point spread function; based on the target blur kernel and the encoded image, a single spectral channel image corresponding to the target wavelength is determined, including: using a digital confocal algorithm to reconstruct the encoded image based on the three-dimensional spectral point spread function to determine the single spectral channel image corresponding to the target wavelength.

[0106] Among them, the specific form of the digital confocal algorithm can refer to the implementation methods in the relevant technology, such as the nearest neighbor method, the linear restoration method, the constrained iteration method, etc., and the present disclosure does not make specific limitations on this.

[0107] In one example, the digital confocal algorithm is a nearest neighbor method, assuming that the encoded image corresponding to the target wavelength is only affected by the adjacent wavelengths. -1 and λ +1 Based on the above process, the adjacent wavelength λ can be determined -1 and λ +1 The corresponding three-dimensional point spread function and coded image can then be used to analyze the adjacent wavelengths λ -1 The corresponding coded image and λ +1 The corresponding coded image is reconstructed to obtain a reconstructed image. Specifically, the adjacent wavelengths λ -1 The corresponding reconstructed image can be expressed as formula (16):

[0108]

[0109] in, Indicates the adjacent wavelength λ -1 The corresponding reconstructed image; g(x, y, λ -1 ) represents the adjacent wavelength λ -1 The corresponding coded image; p(x, y, λ -1 ) represents the adjacent wavelength λ -1 The corresponding three-dimensional point spread function.

[0110] Adjacent wavelength λ -1The corresponding reconstructed image can be expressed as formula (17):

[0111]

[0112] in, Indicates the adjacent wavelength λ +1 The corresponding reconstructed image; g(x, y, λ +1 ) represents the adjacent wavelength λ +1 The corresponding coded image; p(x, y, λ +1 ) represents the adjacent wavelength λ +1 The corresponding three-dimensional point spread function.

[0113] On this basis, based on the nearest neighbor method, the reconstructed image corresponding to the adjacent wavelength is removed from the encoded image corresponding to the target wavelength λ, and the single spectral channel image corresponding to the target wavelength λ can be determined. Specifically, the single spectral channel image corresponding to the target wavelength λ can be expressed as formula (18):

[0114]

[0115] in, represents the single spectral channel image corresponding to the target wavelength λ; c represents the weighting factor, which is used to correct the influence of two adjacent layers on the middle layer. Its specific value can be flexibly set according to actual usage requirements, and the present disclosure does not make specific limitations on this.

[0116] Figure 5 FIG. 2 shows a schematic diagram comparing a coded image and a single spectral channel image according to an embodiment of the present disclosure. Figure 5 As shown in (a) in FIG. 1 , the image represents a coded image corresponding to a target light beam having a target wavelength; Figure 5 As shown in (b), the image represents a single spectral channel image corresponding to the target wavelength.

[0117] In one possible implementation, a single spectral channel image corresponding to the target wavelength is determined based on a target blur kernel and a coded image, including: using a deep learning algorithm to reconstruct the coded image based on the target blur kernel to determine the single spectral channel image corresponding to the target wavelength.

[0118] Among them, the specific form of the deep learning algorithm can refer to the implementation methods in the relevant technology, such as the neural network algorithm, etc., and the present disclosure does not make specific limitations on this.

[0119] In one example, the deep learning algorithm is a neural network algorithm. The target blur kernel and the encoded image can be input into a pre-trained neural network model to obtain a single spectral channel image corresponding to the target wavelength.

[0120] In the disclosed embodiment, by determining the target focusing distance after the target light with the target wavelength passes through the target diffraction lens, the target blur kernel corresponding to the target light at the target focusing distance and the coded image of the target light at the target focusing distance can be determined; according to the target blur kernel and the coded image, the single spectral channel image corresponding to the target wavelength is determined, so that the designated spectral channel can be reconstructed separately without the need to reconstruct other spectral channels other than the spectral channel corresponding to the target wavelength, thereby improving the efficiency and flexibility of spectral imaging. On this basis, by flexibly setting the value of the target wavelength, the spectral resolution can be converted into the resolution of the target focusing distance, so that based on the change of the target focusing distance with the value of the target wavelength, by reconstructing the coded images at the target focusing distances with different values, multiple continuous spectral channel images with higher resolution can be quickly and conveniently obtained.

[0121] It can be understood that the above-mentioned various method embodiments mentioned in the present disclosure can be combined with each other to form a combined embodiment without violating the principle logic. Due to space limitations, the present disclosure will not repeat them. It can be understood by those skilled in the art that in the above-mentioned method of the specific implementation method, the specific execution order of each step should be determined according to its function and possible internal logic.

[0122] In addition, the present disclosure also provides a hyperspectral imaging device based on a diffraction lens, an electronic device, a computer-readable storage medium, and a program, all of which can be used to implement any hyperspectral imaging method based on a diffraction lens provided by the present disclosure. The corresponding technical solutions and descriptions are referred to the corresponding records in the method part and will not be repeated here.

[0123] Figure 6 FIG. 1 is a block diagram of a hyperspectral imaging device based on a diffractive lens according to an embodiment of the present disclosure. Figure 6 As shown, the device 600 includes:

[0124] A focusing distance determination module 601 is used to determine a target focusing distance of a target light beam having a target wavelength after passing through a target diffractive lens;

[0125] A blur kernel determination module 602 is used to determine a target blur kernel corresponding to a target light ray at a target focusing distance;

[0126] An image acquisition module 603 is used to determine a coded image of a target light beam at a target focusing distance;

[0127] The image reconstruction module 604 is used to determine a single spectral channel image corresponding to the target wavelength according to the target blur kernel and the encoded image.

[0128] In a possible implementation, the focusing distance determination module 601 is specifically used to: determine the phase difference generated after the target light passes through the target diffraction lens according to the target wavelength; determine the target focusing distance according to the phase difference generated after the target light passes through the target diffraction lens.

[0129] In a possible implementation, the phase difference generated after the target light passes through the target diffraction lens includes: a first phase difference when the target light passes through any point other than the center point of the target diffraction lens relative to the target light passing through the center point of the target diffraction lens, and a second phase difference caused by the optical path difference when the target light passes through any point other than the center point of the target diffraction lens to propagate to the focus relative to the target light passing through the center point of the target diffraction lens to propagate to the focus; the focusing distance determination module 601 is specifically used to: for any point on the target diffraction lens, determine the first phase difference corresponding to the target light passing through the point according to the target wavelength and the lens surface parameters corresponding to the target diffraction lens; for any point on the target diffraction lens, determine the second phase difference corresponding to the target light passing through the point according to the target wavelength.

[0130] In a possible implementation, the target blur kernel includes a three-dimensional spectral point spread function; the blur kernel determination module 602 is specifically used to: determine the transmittance function corresponding to the target diffraction lens; and determine the three-dimensional spectral point spread function according to the target focusing distance and the transmittance function.

[0131] In one possible implementation, the target blur kernel includes a three-dimensional spectral point spread function; the image reconstruction module 604 is specifically used to: use a digital confocal algorithm to reconstruct the encoded image according to the three-dimensional spectral point spread function to determine a single spectral channel image corresponding to the target wavelength.

[0132] In a possible implementation, the image reconstruction module 604 is specifically used to: utilize a deep learning algorithm to reconstruct the encoded image according to the target blur kernel, and determine a single spectral channel image corresponding to the target wavelength.

[0133] In a possible implementation, the target diffractive lens is processed according to the target lens surface parameters, wherein the target lens surface parameters are determined according to the center wavelength, the center focal length and the material refractive index corresponding to the target material, and the target material represents the material used to process the target diffractive lens.

[0134] In some embodiments, the functions or modules included in the device provided by the embodiments of the present disclosure can be used to execute the method described in the above method embodiments. The specific implementation can refer to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0135] The embodiment of the present disclosure also provides a computer-readable storage medium on which computer program instructions are stored, and the computer program instructions implement the above method when executed by a processor. The computer-readable storage medium can be a volatile or non-volatile computer-readable storage medium.

[0136] An embodiment of the present disclosure further proposes an electronic device, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to implement the above method when executing the instructions stored in the memory.

[0137] Figure 7 1900 is a block diagram of an electronic device according to an embodiment of the present disclosure. For example, the apparatus 1900 may be provided as a server or a terminal device. Figure 7 , the apparatus 1900 includes a processing component 1922, which further includes one or more processors, and a memory resource represented by a memory 1932 for storing instructions, such as an application, that can be executed by the processing component 1922. The application stored in the memory 1932 may include one or more modules, each corresponding to a set of instructions. In addition, the processing component 1922 is configured to execute instructions to perform the above method.

[0138] The device 1900 may also include a power supply component 1926 configured to perform power management of the device 1900, a wired or wireless network interface 1950 configured to connect the device 1900 to a network, and an input / output interface 1958 (I / O interface). The device 1900 may operate based on an operating system stored in the memory 1932, such as Windows Server 2000. TM , MacOS X TM , Unix TM ,Linux TM , FreeBSD TM or similar.

[0139] In an exemplary embodiment, a non-volatile computer-readable storage medium is also provided, such as a memory 1932 including computer program instructions, which can be executed by the processing component 1922 of the device 1900 to perform the above method.

[0140] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0141] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0142] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0143] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0144] Various aspects of the present disclosure are described herein with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer-readable program instructions.

[0145] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0146] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operating steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0147] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to multiple embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of the module, program segment or instruction includes one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of special hardware and computer instructions.

[0148] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A hyperspectral imaging method based on a diffraction lens, characterized in that: include: Determine a target focusing distance of a target light beam having a target wavelength after passing through a target diffractive lens; Determine a target blur kernel corresponding to the target light at the target focusing distance; Determining a coded image of the target light at the target focusing distance; A single spectral channel image corresponding to the target wavelength is determined according to the target blur kernel and the encoded image.

2. The method according to claim 1, characterized in that The step of determining a target focusing distance of a target light beam having a target wavelength after passing through a target diffractive lens comprises: Determining, according to the target wavelength, a phase difference generated after the target light passes through the target diffraction lens; The target focusing distance is determined according to the phase difference generated after the target light passes through the target diffraction lens.

3. The method according to claim 2, characterized in that The phase difference generated after the target light passes through the target diffractive lens includes: a first phase difference when the target light passes through any point other than the center point of the target diffractive lens relative to the center point of the target light passing through the target diffractive lens, and a second phase difference generated due to an optical path difference when the target light passes through any point other than the center point of the target diffractive lens to propagate to the focus relative to the center point of the target light passing through the target diffractive lens to propagate to the focus; The step of determining, according to the target wavelength, a phase difference generated after the target light passes through the target diffractive lens comprises: For any point on the target diffractive lens, determine a first phase difference corresponding to the target light passing through the point according to the target wavelength and the lens surface parameters corresponding to the target diffractive lens; For any point on the target diffractive lens, a second phase difference corresponding to the target light passing through the point is determined according to the target wavelength.

4. The method according to any one of claims 1 to 3, characterized in that The target blur kernel includes a three-dimensional spectral point spread function; The determining of the target blur kernel corresponding to the target light at the target focusing distance includes: Determining a transmittance function corresponding to the target diffractive lens; The three-dimensional spectral point spread function is determined according to the target focusing distance and the transmittance function.

5. The method according to claim 4, characterized in that The target blur kernel includes a three-dimensional spectral point spread function; The step of determining the single spectral channel image corresponding to the target wavelength according to the target blur kernel and the encoded image includes: The coded image is reconstructed according to the three-dimensional spectral point spread function by using a digital confocal algorithm to determine a single spectral channel image corresponding to the target wavelength.

6. The method according to any one of claims 1 to 3, characterized in that: The step of determining the single spectral channel image corresponding to the target wavelength according to the target blur kernel and the encoded image includes: The encoded image is reconstructed according to the target blur kernel by using a deep learning algorithm to determine a single spectral channel image corresponding to the target wavelength.

7. The method according to any one of claims 1 to 3, characterized in that The target diffractive lens is processed according to the target lens surface parameters, wherein the target lens surface parameters are determined according to the center wavelength, the center focal length and the material refractive index corresponding to the target material, and the target material represents the material used to process the target diffractive lens.

8. A hyperspectral imaging device based on a diffraction lens, characterized in that: include: A focusing distance determination module, used to determine a target focusing distance of a target light beam having a target wavelength after passing through a target diffractive lens; A blur kernel determination module, used to determine a target blur kernel corresponding to the target light at the target focusing distance; An image acquisition module, used to determine a coded image of the target light at the target focusing distance; An image reconstruction module is used to determine a single spectral channel image corresponding to the target wavelength according to the target blur kernel and the encoded image.

9. An electronic device, characterized in that: include: processor; a memory for storing processor-executable instructions; The processor is configured to implement the method described in any one of claims 1 to 7 when executing the instructions stored in the memory.

10. A non-volatile computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images